Telegraph relay



July 28 1925.

. J. P. FERRITER ET AL TELEGRAPH RELAY Filed Aug- 29. 1923 Exp??? 5V7?Sign 065 601711612607" 15 used Patented July 28, 1925.

UNITED STATES "1,547,856 PATENT OFFICE.

JOHN P. FERRITER, 0F OCEANI'OBT, AND WEIGHT H. JOHNSON, 0F RED B ANK,NEW JERSEY.

TELEGRAPH RELAY.

Application filed August 29, 1923. Serial N0. 660,024.

To all whom it may concern:

Be itknown that We, JOHN P. FERRITER and WRIGHT H. JOHNSON, citizens ofthe United States, residing, respectively, at Oceanport and Red Bank, inthe county of Monmouth and State of New Jersey, have invented certainnew and useful Improvements in Telegraph Relays, of whichthe followingis a-specification.

The invention relates to alternating cur.- rent telegraphic devicesemploying vacuum tubes or the like and has for one of its principalobjects to provide an amplifylng method of reception that so coordinatesthe opposite alternating current impulses as to cooperate in working arecelver or relay.

A further object is the application of such invention to a duplex systemalthough it may be employed quite generally. In general it should beunderstood that where alternating currents of low frequency areemployed, the system disclosedherernaft is especially adaptable for theselective reception of several frequencies over one and the samefiltered line.

Further features of the invention are hereinafter described in detalland illustrated in the accompanying drawlngs 1n which:

Figure 1 is a circuit dlagram of the arrangement of working duplex recept1on.

Figure 2 is a diagrammatlc' lllustratlon of the rectificationcurrents'upon the relay. Figure 3 is a diagrammatic illustration of theeffects of the relay condenser.

Referring'more particularly to the drawings, M is an iron coretransformer havmg the primary windings O and O and secondary windings Pand P Outgoing l1 ne current is introduced into the middle point of theprimary windings s by means of the transformer T. The coils O and O, areconnected respectively to the line and the artificial line and replacethe line and the artificial line coils of the ordinary type of relay. Abalance is established by varying the artificial line resistance just as1n the I case of the ordinary direct current duplex.

Since the system is balanced to outgoing signals, there will be nopotential. induced in the coils P and P In the case of incoming signalsthere is an unbalance due to the fact that the windings O and thesecondary of the transformer T form parallel paths to the ground.

A voltage will therefore be induced in the windings P and P Tubes 1 and2 are three-electrode vacumntubes lighted by the filament battery A. Theplate potential is furnished by the battery B through the windings ofthe relay R. The grids are kept strongly negative by means of thebattery C. The grids of the tubes are connected to the terminals ofcoils P and P respectively.

Suppose that a given half cycle induces a positive potential on the gridof tube 1. An increase in current in the plate circuit of tube 1 throughthe windings of the relay R results and the relay is actuated. At thesame instant a negative potential is applied to the grid of tube 2. Thisgrid is already negative due to battery G and on account of thecurvature of the characteristic of the tube, there is no decrease inplate current of tube 2 due to its grid potential becoming of tube 1becomes negative so that an increase in current in the plate circuit oftube 2 through the windings of the relay R results so that the relayremains closed.

The result is that an alternating-current impressed on'the grids of thetubes 1 and 2. produces a pulsating direct current through the windingsof the relay R. (Figure 2.) The action of the condenser K 1s to smoothout the pulsating current and keep the relay from chattering. Figure 3shows the relay current when the condenser K is used.

An opposing coil X in the relay is used in connection with the battery Yand the variable resistance Z to give proper bias to the relay and tocounteract the efiect of the steady direct current component of theplate current on the relay.

The system above described will operate on any alternating current ofany frequency. It can be applied to one way, duplex and quadrupletelegraphy.

Having thus described our invention, we

claim combination with. a line source of alternating current, aplurality of rectify- 110 76 more negative; At the next half cycle thegrid of tube 2 becomes'positive and the grid The advantages to be gainedby the use of this device are that ing amplifier vacuum tubes excited bysaid line source, at least one of said plurality of tubes in each leg ofsaid exciting source anda relay operated by the unidirectional currentsinduced by both halves of said alternating current source, and anexciting direct current coil means to give to said relay a proper biasduring operation.

2. In combination with a line source of alternating current, a pluralityof rectifying amplifier vacuum tubes excited by said line source, atleast one of said plurality of tubes in each leg of said excitingsource, a

direct current amplifying source for said amplifier vacuum tubes, and arelay operated by the unldlrectional currents lnduced by both halves ofsaid alternating current source, and drawingits owcr from said directcurrent source, an an exciting direct current coil means to give to saidrelay a proper bias against the steady effect ofsaid direct currentamplifying source.

In testimony whereof. we aifix our signatures.

. JOHN P. FERRITER.

WRIGHT H. JOHNSON.

